Stomach pain and dark stool on day 6 of water fast

Hey people I'm on day 6 of my 10 day water fast. Since yesterday I've had really painful heartburn in my stomach, which is really warm by the way. I get moderate releaf when I sit myself up however it makes trying to sleep unbearable sometimes. I read that this is fairly normal and that adding lemon squeeze to my water might give me some relief but wouldn't that interfering with the fast? Now what really worries me is when I woke up this morning I was quite dehydrated and somewhat dizzy alongside nausea, I not long after passed a sludge stool that was very dark, it looked black however when I wiped my bum there was no blood which leaves me to believe it was dark brown regardless I'm rather concerned. I'm considering breaking my fast tomorrow night if the heartburn doesn't subside but i thought I'd bring it to the forums to ask your opinion. Does this seem normal? Should I attempt to push on? Or should I get medical attention? Tweet